title: Left atrial responses to acute right ventricular apical pacing in patients with sick sinus syndrome.
abstract: Chronic right ventricular apical (RVA) pacing can lead to an increased risk of heart failure and atrial fibrillation, but the acute effects of RVA pacing on left atrial (LA) function are not well known. Twenty-four patients with sick sinus syndrome and intact intrinsic atrioventricular conduction were included. All patients received dual-chamber pacemaker implants with the atrial lead in the right atrial appendage and the ventricular lead in the right ventricular (RV) apex. Transthoracic standard and strain echocardiography (measured by tissue Doppler imaging and speckle tracking image) were performed to identify functional changes in the left ventricle (LV) and LA before and after 1 hour of RVA pacing. The LA volume index did not change after pacing; however, the ratio of peak early diastolic mitral flow velocity (E) to peak early diastolic mitral annular velocity (Ea) was significantly increased and peak systolic LA strain (Sm), mean peak systolic LA strain rate (SmSR), peak early diastolic LA strain rate (EmSR), and peak late diastolic LA strain rate (AmSR) were significantly reduced after RV pacing. LV dyssynchrony, induced by RV pacing, had a significant correlation with E/Ea, Sm, and SmSR after pacing. E/Ea also had a negative correlation with Sm and SmSR after pacing. Multivariate regression analysis identified LV dyssynchrony and E/Ea as important factors that affect Sm, SmSR, EmSR, and AmSR after acute RVA pacing. Acute RVA pacing results in LA functional change and LV dyssynchrony and higher LV filling pressures reflected by E/Ea are important causes of LA dysfunction after acute RVA pacing.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Maryknoll Medical Center, Busan, South Korea.
authors.forename: Seong-Man
authors.initials: SM
authors.lastname: Kim
authors.forename: Kyoung-Im
authors.initials: KI
authors.lastname: Cho
authors.forename: Tae-Joon
authors.initials: TJ
authors.lastname: Cha
authors.forename: Jung-Ho
authors.initials: JH
authors.lastname: Heo
authors.forename: Hyun-Su
authors.initials: HS
authors.lastname: Kim
authors.forename: Jae-Woo
authors.initials: JW
authors.lastname: Lee
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012804:Sick Sinus Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D016896:Treatment Outcome
keywords: artificial; cardiac pacing; echocardiography; left atrial function; left ventricular function